feat(cli-logs): Configure and format SAM CLI logging to console (#1118)

samcli/cli/context.py

@@ -45,7 +45,8 @@ def debug(self, value):
 
         if self._debug:
             # Turn on debug logging
-            logging.getLogger().setLevel(logging.DEBUG)
+            logging.getLogger('samcli').setLevel(logging.DEBUG)
+            logging.getLogger('aws_lambda_builders').setLevel(logging.DEBUG)
 
     @property
     def region(self):

samcli/cli/main.py

@@ -8,6 +8,7 @@
 
 from samcli import __version__
 from samcli.lib.telemetry.metrics import send_installed_metric
+from samcli.lib.utils.sam_logging import SamCliLogger
 from .options import debug_option, region_option, profile_option
 from .context import Context
 from .command import BaseCommand
@@ -79,7 +80,6 @@ def cli(ctx):
     You can find more in-depth guide about the SAM specification here:
     https://github.com/awslabs/serverless-application-model.
     """
-
     if global_cfg.telemetry_enabled is None:
         enabled = True
 
@@ -95,3 +95,10 @@ def cli(ctx):
 
         except (IOError, ValueError) as ex:
             LOG.debug("Unable to write telemetry flag", exc_info=ex)
+
+    sam_cli_logger = logging.getLogger('samcli')
+    sam_cli_formatter = logging.Formatter('%(message)s')
+    lambda_builders_logger = logging.getLogger('aws_lambda_builders')
+
+    SamCliLogger.configure_logger(sam_cli_logger, sam_cli_formatter, logging.INFO)
+    SamCliLogger.configure_logger(lambda_builders_logger, sam_cli_formatter, logging.INFO)

samcli/lib/utils/sam_logging.py

@@ -0,0 +1,31 @@
+"""
+Configures a logger
+"""
+import logging
+
+
+class SamCliLogger(object):
+
+    @staticmethod
+    def configure_logger(logger, formatter, level):
+        """
+        Configure a Logger with the formatter provided.
+
+        Parameters
+        ----------
+        logger logging.getLogger
+            Logger to configure
+        formatter logging.formatter
+            Formatter for the logger
+
+        Returns
+        -------
+        None
+        """
+        log_stream_handler = logging.StreamHandler()
+        log_stream_handler.setLevel(logging.DEBUG)
+        log_stream_handler.setFormatter(formatter)
+
+        logger.setLevel(level)
+        logger.propagate = False
+        logger.addHandler(log_stream_handler)

tests/unit/cli/test_context.py

@@ -19,7 +19,8 @@ def test_must_set_get_debug_flag(self):
 
         ctx.debug = True
         self.assertEquals(ctx.debug, True, "debug must be set to True")
-        self.assertEquals(logging.getLogger().getEffectiveLevel(), logging.DEBUG)
+        self.assertEquals(logging.getLogger('samcli').getEffectiveLevel(), logging.DEBUG)
+        self.assertEquals(logging.getLogger('aws_lambda_builders').getEffectiveLevel(), logging.DEBUG)
 
     def test_must_unset_get_debug_flag(self):
         ctx = Context()

tests/unit/lib/utils/test_sam_logging.py

@@ -0,0 +1,25 @@
+from unittest import TestCase
+from mock import patch, Mock
+
+from samcli.lib.utils.sam_logging import SamCliLogger
+
+
+class TestSamCliLogger(TestCase):
+
+    @patch("samcli.lib.utils.sam_logging.logging")
+    def test_configure_samcli_logger(self, logging_patch):
+        formatter_mock = Mock()
+        logger_mock = Mock()
+        logging_patch.DEBUG = 2
+
+        stream_handler_mock = Mock()
+        logging_patch.StreamHandler.return_value = stream_handler_mock
+
+        SamCliLogger.configure_logger(logger_mock, formatter_mock, level=1)
+
+        self.assertFalse(logger_mock.propagate)
+
+        logger_mock.setLevel.assert_called_once_with(1)
+        logger_mock.addHandler.assert_called_once_with(stream_handler_mock)
+        stream_handler_mock.setLevel.assert_called_once_with(2)
+        stream_handler_mock.setFormatter.assert_called_once_with(formatter_mock)